Electric-contact protector



(No Model.) B VARLEY, J1.

ELECTRIC CONTACT PROTECTOR. No. 449,302. Patented MarQBl, 1891.

UNITED STATES PATENT OFFICE.

RICHARD VARLEY, JR, OF ENGLEXVOOD, NEW JERSEY.

ELECTRIC-CONTACT PROTECTOR.

SPECIFICATION forming part of Letters Patent No. 449,302, dated March31, 18 91.

Application filed November 28, 1890. Serial No. 372,842. (No model.)

T0 at whom it may concern.-

Be it known that I, RICHARD VARLEY, J r., of Englewood, in the county ofBergen and State of New Jersey, have invented an Electric-ContactProtector, of which the following is a specification.

In call-bells that are operated electrically great difficulty hasheretofore been experienced in consequence of particles of dust or otherforeign substances getting in between the normally-separated contactpoints or surfaces, and the risk of the alarm becoming inoperative isaugmented by the fact that considerable periods of time often elapse between one use and the next of the alarm or call.

My present invention is for effectually excluding dust and any foreignsubstance from normally-separated electric contact points or surfaces inelectric call-bells, so that such surfaces are maintained in a clean andfullyoperative condition for an indefinite period, and the risk ofoxidation is very largely removed, because the atmosphere is so fullyexcluded that any fresh supply of oxygen will be cut off and the sparkwill not injure the metallic surfaces.

In the drawings, Figure l is a plan View of an electric call-bell fittedwith my improve-- ment, and Fig. 2 is a sectional elevation of theelectrodes and protector in larger size.

Two contacts or electrodes A and B are represented, the contactA beingin the form of a screw with a platina plug, and the contact B being upona spring 0, attached to the armature of the hammer D.

The'protectorE is elastic and of'insulating material that extends fromone contact to the other, forming an inclosure for such contacts. It isadvantageous to make use of thin soft india-rubber.

The protector is made of two small disks of rubber with a centralopening in each disk and the disks united together around the edges andvulcanized, and one disk is around the button-head of the contact B, andthe other disk is around the end of the screw A, and its inner edgewithin an annular groove, so that the screw can be rotated in adjustingthe contact or back-stop; but the atmosphere will be substantiallyexcluded and no dust or foreign matter can come between the normally-separated contact-surfaces. Hence they will always be in operativecondition; and it is not necessary to inclose the hell or magnet in acase, as has sometimes been done to aid in keeping the alarm or similarelectric device in Working order. The protector can be similarly madefor the contacts of a telegraphkey, the contact pins or studs having bypreference heads with annular channels or necks for the edges of theelastic protector.

In consequence of using flat disks of rubber united around their edgesthe protector occupies but little space and does not present anyperceptible resistance to the movement of the electrode. Hence theinstruments and adjustments do not require to be changed for receivingthe dust-protector.

I claim as my invention- An electric-contact protector formed of twodisks of flexible material connected together around their edges andhaving central openings for the electrodes.

Signed by me this 20th day of November, 1890.

RICHARD VARLEY, JR.

Witnesses:

GEO. T. PINOKNEY, WILLIAM G. lVIOT'I.

